Or worse, ask someone who lost a loved one. Like a beloved daughter. Or an eight-year-old son, who stares back now only from a photo, his bright, young face lit up with a smile of joy and innocence.

For the Boston Marathon and the beloved tradition that is Patriot’s Day in Boston, joy and innocence seem to have joined the casualty list, too.

Let’s face it, for Bostonians, that’s part of what stings so deeply and hurts so much.

The third Monday in April—Patriots Day—is, without question, the best day of the year in Boston. It is a kaleidoscope of energy and activity, beginning literally before the sun comes up: there is the reenactment of the “shot heard round the world” on the Lexington town green at dawn; the Red Sox traditional 11am game at Fenway; and the Boston Marathon which, bless the perseverance of the runners who refuse to quit, doesn’t bring down the final curtain on the day until dusk.

I have never done the “tri-fecta”—present to see some of all three events—but I’ve frequently done two out of three. My own family has made a tradition of rising in the dark, driving to Lexington, and standing with hundreds of others in the pre-dawn spring chill, awaiting the stirring sound of hooves making their way up Massachusetts Ave., warning of the British advance.

From there, we go home, eat some breakfast, and head back out to take up our own positions at the ready, poised to hear a different advance, and to spy the Marathon’s first lead runners, still fairly fresh and footloose. (But then, they’re only in Ashland, a mere five miles or so in.)

There is an exuberance and collective spirit that makes the Marathon—and Patriots Day—unique and like nothing else anywhere. The sad irony is that those very things that make the Boston Marathon so special, so beloved, are also the very things that helped attract an act of terror to begin with. The more bittersweet irony is that they are also the very things that should give us a measure of comfort now in terror’s aftermath.

Anyone who has run Boston, or simply lined the route like me and my daughters, knows that those cheering crowds lend a boost that no tailwind can ever match. On Heartbreak Hill, crowds literally will faltering runners back on the course: “Don’t get on the bus!” is a common crowd refrain to those staggering runners inching toward a merciful ride to the Finish Line. And I have seen a runner or two literally respond like a banged-up boxer, drawing new, if uncertain life from the crowd, and turning back to the course with a sudden new determination to keep going. The crowd erupts, and I defy anyone who’s witnessed that very scene not to get choked up. I sure have.

That’s the spirit of the Boston Marathon. That’s the spirit of Boston. Runners who refuse to quit; people who cheer them on and refuse to let them quit.

Boston, it’s often said, is a tough town. Not the friendliest place.

If that theory is true, it’s not one you’d want try and prove on Patriots Day.

On Patriots Day, Boston welcomes the world. The cheers along the route make no distinctions. You’re here, we cheer, you go, whoever you are and wherever you’re from!

When the first explosion rocked Boylston Street, a row of international flags bent with the blast. But they didn’t break. They’ll stand again at proud attention a year from now.

From Atlanta, to Oklahoma City, to 9/11, and now to Boston, America has endured its own kind of macabre marathon—a grinding, grievous process of pain, endurance, and hard-won experience. Like a marathon, we keep going. There is no bus to retreat to, there is no vantage point to see the way forward, and there is no finish line to point to a blessed end.

But we know what chokes us up when we cheer those runners in Boston—their determination and resolve, and our collective comfort, support, and goodwill. That’s the spirit of a marathon. That’s the spirit of Boston, where the smoke has cleared, the tears are drying, and those laid low will be remembered. And that spirit will turn back to the course, and keep running.

The Obama administration will unveil a major climate change plan Monday aimed at a large reduction in greenhouse gas emissions from the nation's coal-burning power plants, a senior administration official told CNN.